Control system for motor driven apparatus



Oct. 23, 1934. P. B. HARWOOD ET AL CONTROL SYSTEM FOR MOTOR DRIVEN APPARATUS Filed March 19. 1952 Patented Oct. 23, I934 UNITED STATES PATENT orsics CONTROL SYSTEM FOR MOTOR DRIVEN APPARATUS Paisley B. Harwood and Niels L. Mortensen, Milwaukee, Wis., assignors to Cutler-Hammer, Inc., Milwaukee, Wis., a corporation of Delaware Application March 19, 1932, Serial No. 600,000 8 Claims. (Cl. 2422-75) This invention relates to control systems for in a counterclockwise direction, spider 8 causes motor driven apparatus, and while not limited links 7 to straighten and move the parts 4 radithereto is particularly applicable to systems for ally so as to increase the eilective diameter of the governing the operation of motor driven reels reel. Drum 5 also carries cooperating stationary 5 such as are employed in connection with mills and movable jaws and'll. Jaw 11 is operatively for rolling strip steel. connected to spider 8 and upon movement of parts In the manufacture of various materials such {1 to their expanded positions said jaw is adapted as cold rolled strip steel the finished product is to cooperate with jaw 10 to grip theforward end wound in coil form upon a reel. In winding such of strip 2. When the material is gripped and the 3 material it is desirable to maintain a predeterreel is rotated in a counterclockwise direction mined substantially constant tension thereon, and sufficiently to tension the strip, brake 9 can be it is also desirable if the mill is stopped for any released and the tension on the strip acting in opreason, as for example to permit gauging of the position to the driving force on the reel serves to material, to maintain tension on the material to maintain parts 4 in their expanded positions. An

15 prevent loosening thereof upon the reel. electromagnetic brake B is also associated with The present invention has among its objects to drum 5 for eilecting collapse of the reel as hereprovide an improved control system for motor inafter set forth. driven reels which meets the above noted require- As shown in Fig. 1, mill 3 is provided with a merits. driving motor 12 and reel 1 is arranged to be driv- 20 Another object is to provide an improved conen through the medium of an electromagnetic trol system of the aforesaid character which proclutch C by a motor 14. A push button controlled vides forquick starting of the reel for taking up starter 15 of any suitable type is provided for 01' slack in the material upon commencement of starting and stopping the mill motor 12, and a the winding operation, and which prevents excontroller 16 or the character shown in Fig. 2 is Z5 cessive pull upon the material when the same beprovided ror controlling the reel 1. comes taut. As shown in Fig. 2 the reel motor 14 is of an ad- Various other objects and advantages of the Justable speed direct current type, the same havinvention will hereinafter appear. ing an armatureA, a series field winding F and a The accompanying drawing illustrates a conshunt field winding F, the latter being connected 30 trol system embodying the invention which will across a supply circuit indicated by lines L -L in now be described, it being understood that the series with an adjustable regulating resistance system may be used in installations of various R. The control means for said motor includes types, and that the same may be modified in electroresponsive line switches 20 and 21, electrovarious respects without departing from the spirit pon iv ac ler in w h 3 and 4.

35 and scope of the appended claims. and an electroresponsive regulating switch 25.

In the drawing, Switches 20 and 21 provide for connection of the Figure 1 schematically illustrates the invenarmature A and series field winding F of the tion as applied to a collapsible reel associated motor across lines L L inseries with resistance with a mill for rolling strip steel, and sections R'-', R R and R Switches 22, 23 and 24 40 Fig. 2 diagrammatically illustrates the circuits are arranged to shunt resistance sections R, R and apparatus for controlling the reel shown in and R respectively, and are controlled to close Fig. 1. progressively after suitable intervals in accord Referring to Fig. 1, the same illustrates a reel ance with any known system of acceleration. 1 for winding strip material 2 as the same passes Regulating switch 25 is arranged to shunt a por- 45 from the finishing rolls of a mill 3. The reel iltion of resistance R in the shunt field circuit 0 lustrated is of a type commonly employed in conof the motor, and the same is controlled as herenection with mills for rolling strip steel, and ininafter set forth to regulate the shunt field cludes a plurality of collapsible parts 4 which strength of the motor so as to maintain a subare arranged to slide radially within suitable restantially constant tension on the material during 50 cesses in a cylindrical drum 5. Drum 5 is rotatwinding thereof. ably mounted upon a shaft 6 and the collapsible An electroresponsive switch 26 is provided for parts 4 are connected by links 7 to a spider 8 connecting the operating winding of clutch C fixed to said shaft. Drum 5 has a foot operated across lines L --L in series with resistance secbrake 9 associated therewith, and when said part tions R", R. and R Resistance sections R", R

:5 is restrained by said brake and shaft 6 is rotated and R. are normally shunted by an electroresponsive switch 2'7 having an operating winding 2'7 connected in series with the operating winding of clutch C and normally open electroresponsive switches 28 and 29 are provided for shunting resistance sections R and B, respectively. The system also includes an electroresponsive switch 30 for connecting the operating winding of brake B across lines L L''.

The control means for the aioredescribed switches includes a plurality of electroresponsive relays and controlling push buttons which will now be described.

An electroresponsive relay 31 is provided for controlling energization of line switches 20 and 21 associated with the reel motor 14, and said relay also serves to establish connections which provide for energization of the clutch C and brake B by an electreresponsive relay 34. The energizing circuit for reiay 31 is controlled by a normally closed push button 32 and a normally open push button 33 and the energizing circuit for relay 34 is under the control of an electroresponsive relay 35 controlled by a normally closed push button 36 and a normally open push button 3'7. Relay 35 also serves to establish connections which provide for energization of regulating switch 25 by normally closed contacts 24 associated with accelerating switch 24 or by a normally open relay 38 having an operating winding 38* connected across resistance section R An electroresponsive relay 39 is provided for establishing an energizing circuit for the clutch resistance control switch 29 through the medium of relays 31, 34 and 35, and as hereinafter set forth the energizing circuit for relay 39 is under the control of certain of the aforementioned relays and is also controlled by a relay 40 associated with the mill starter 15. As hereinbefore stated, starter 15 is of a push button controlled type and as shown in Fig. 2 the operating winding of relay to is arranged to be connected across a supply circuit indicated by lines L ---L by the stop push button 41 of said starter. The clutch control switch 23 is controlled by a normally closed electroresponsive timing relay 42. This relay is provided with a dash pot for retarding closing movement thereof and its energizing circuit is controlled by an electroresponsive relay 43 associated with starter 15. As shown in Fig. 2, the operating winding of relay 43 is adapted to be connected across the supply circuit L -L by the stop push button 41 of starter 15 and auxiliary contacts 44 which it is assumed are associated with the line switch of said starter and are adapted to close upon establishment of power connections for the mill motor 12. The system also includes a limit switch 45 which as hereinafter set forth controls a maintaining circuit for relay 39. Said limit switch is associated with the reel and is adapted to open when the reel is in proper position to receive a strip.

The operation of the circuit connections of the aforedescribed system will now be more fully set forth.

The reel motor is started by depressing push button 33. Closure of push button 33 effects response of relay 31 by connecting the operating winding thereof across lines L --l' through the medium of push button 32. Upon response of relay 31 the contacts 31 thereof shunt push button 33 to maintain said relay in closed position and the contacts 31' thereof connect the operating windings of line switches 20 and 21 in parallel across lines LL Switches 20 and 21 therefore respond to connect the armature A and series field winding F of reel motor 14 across lines L -L in series with resistance sections R. to R inclusive. Accelerating switches 22, 23 and 24 then respond progressively aIter suitable intervals to exclude resistance sections R, R and R During starting or motor i l the operating winding of regulating switch 25 is connected across lines Il -4.1 by the auxiliary contacts 24 associated with accelerating switch 24 and contacts 35 associated with relay 35. Switch 25 is thus held in closed position, and as is apparent the same shunts a portion of regulating resistance R to provide maximum current in the shunt field winding pending response of accelerating switch 24. Upon closure of accelerating switch 24 the contacts 24; thereof open to deenergize switch 25 and the current in the shunt field winding F is reduced to provide for operation oi the reel motor at a predetermined high speed determined by the adjustment of resistance R To effect stopping of the reel motor 14 at any time push button 32 is depressed and relay 31 then drops out to deenergize the line switches 20 and 21.

When a strip 2 comes through the finishing rolls 3 of the mill the reel motor 14 is in operation and the operator then inserts the forward end of the strip betweenjaws l0 and 11 of reel 1 and simultaneously closes push button 37 and applies brake 9. To simplify this operation push button 3'? is preferably associated with brake 9 so that the same closes when said brake is applied. Closure of push button 3'? effects response of relay 35 by connecting the operating winding of said relay across lines L L through the medium of normally closed push button 36. Relay as responds immediately upon response of relay 35, the operating winding thereof being then connected across lines L -L through the medium of push button 36 and the contacts 35 of relay 35. Response of relay as effects closure of the clutch control switch 26 and the brake control switch 30 since the operating windings of these switches are then connected in parallel across lines L --L through the medium of contacts 31* of. relay 31 and contacts 3 of relay 34. Closure of switch 26 connects the operating winding of clutch C directly across lines il -L through the medium of relay 2'? to effect quick engagement of said clutch and closure of switch 30 connects the operating winding of brake B directly across said lines to eiiect quick release of said brake.

Reel 1 now begins to rotate in a counterclockwise direction and upon initial rotation thereof brake 9 causes the jaws 10 and 11 of said reel to grip the strip 2 and the parts 4 thereof to move to their expanded positions. The strip is then wound upon the expanded reel and since the reel motor is operating at high speed due to inclusion of regulating resistance R in the shunt field circuit thereof the reel is accelerated rapidly to eifect quick take-up of the slack between the reel and the rolls 3. Before the strip between the reel and rolls 3 becomes taut the current in the clutch winding 0 builds up to a value sufficient to effect response of relay 27. Response of relay 27 in cludes resistance sections R and R in series with the operating winding of clutch C, the resistance section R being at this time shunted by switch 28 which is energized through the medium of timing relay d2. The current in the clutch winding is thus reduced to a value which provides for slippage of the clutch at a torque which is insufficient to produce excessive strain on the strip when the same becomes taut.

Upon taking up of the slack between the reel 1 and the rolls 3 the operator releases brake 9 and push button 3'7. Relay 35 is then deenergized but upon dropping out of said relay relay 34 is maintained energized by a circuit extending through its contacts 34 and the normally closed push button 36. As is apparent, when the mill is in operation relays 40 and 43 are held in their attracted positions as shown in the drawing, and upon dropping out of relay 35 relay 39 is energized by a circuit extending from line L through push button 36 through contacts 34 of relay 34, through relay 40 to and through the operating winding of relay 39 and through contacts 43 of such resistance increases the current in the operating winding of the clutch to a value which prevents slippage of the clutch during the winding operation.

During winding operations relay 38 acts through the medium of regulating switch 25 to control the speed of reel motor 14 in a manner whereby a predetermined substantially constant tension is maintained'on the strip. When the tension on the strip exceeds a predetermined value, the current in the armature circuit of motor 14 effects response of relay 38. The operating winding of regulating switch 25 is then connected across lines L --L through the medium of contacts 35 of relay 35 and said switch responds to shunt a portion of the regulating resistance R to thereby increase the current through shunt'fleld winding F This causes the motor 14 to slow down, which in turn reduces the tension on the strip 2 and consequently reduces the load on said motor. Upon a given reduction of the load on motor 14 relay 38 drops out to deenergize regulating switch 25, whereupon the above regulating cycle will be repeated. It will thus be apparent that the action of relay 38 will be vibratory to thereby maintain a predetermined average tension on strip 2.

When it is desired to stop the mill for any reason, as for example to permit gauging oi the material, push button 41 is momentarily depressed, and as hereinbefore stated this operation causes controller 15 to effect stopping or the mill motor 12. Relay 40 then drops out momentarily to interrupt the aforedescribed energizing circuit for relay 39 and relay 43 drops out to prevent reestablishment of this energizing circuit pending restarting oi the mill motor 12. Upon deenergization of relay 39 the contacts 39 thereof interrupt the aforesaid energizing circuit for switch 29 and said switch thus moves to open position to insert resistance section R in series with the operating winding of clutch C. Also upon dropping out of relay 43 the contacts 43 thereof connect the operating winding of timing relay 42 across lines L -L' and said relay in responding deenergizes switch 28 to include re sistance section R" in series with the operating winding of clutch C. Thus during stopping of the mill resistance sections R", R and R are included in circuit with the operating winding of clutch C and such resistances limit current in the clutch circuit to a value sufilcient to maintain switch 27 in closed position and to provide for" slippage of the clutch at a torque of low value which maintains suiiicient tension on the strip to prevent collapse 0! the reel upon stopping of the mill.

When the mill is restarted relay 43 is energized by auxiliary contacts 44 associated with the mill controller, and upon response of relay 43 the aforedescribed energizing circuit for relay 39 is reestablished and also timing relay 42 is deenergized to permit closure thereof against the action of its associated dash pot. Relay 39 in responding .reestablishes the aforedescribed energizing circuit for switch 29 and after a period which is suflicient for the mill to be brought up to speed relay 42 returns to normal position to reestablish the ai'oredescribed energizing circuit for switch 28. Thus during restarting of the mill resistance section R is first shunted to provide for slippage of the clutch at a given increased torque, and when the mill is brought up to speed resistance section R is shunted to prevent slippage of the clutch upon continuance of the winding operation.

To stop the reel upon completion of a coiling operation, push button 36 is depressed and if the reel is then in the proper position for receiving the next strip the aioredescribed energizing circuit for relay 34 is interrupted and said relay in dropping out deenergizes the clutch control switch 26 and brake control switch 30-. Clutch C is thus released and the reel is brought to a quick ::top and collapsed under the action of brake B.

If the reel is not in the proper position for receiving the next strip, at the moment push button 36 is depressed the limit switch 45 associated with the reel is closed and maintains a' shunt circuit around said push button to prevent dropping out of relay 34. However, if push button 36 is maintained depressed until the reel arrives at the proper position for receiving the next strip, limit switch 45 opens and relay 34 then drops out to stop the reel as above set forth. Upon completion of a winding operation the reel motor remains in operation, but as is apparent the same may be stopped at any time by depressing push button 32.

What weclaim as new and desire to secure by Letters Patent is:

l. The combination with a revoluble reel for coiling stock fed thereto, of driving means for said reel including an electromagnetic clutch and means for controlling said clutch including means for limiting the torque transmitted thereby upon commencement of a coiling operation and also upon arrest of the stock during a coiling operation.

2. The combination with a machine operating to deliver stock to be coiled and a revoluble reel for the coiling of such stock, of a driving motor A for said reel, an electromagnetic clutch for establishing a driving connection between said reel and said motor, and means for controlling energization of said clutch including means for varying the current supplied thereto to provide for limitation of the torque transmitted thereby upon commencement of a winding operation and also upon stopping of said machine.

3. The combination with adelivery means for stock to be coiled and a revoluble reel for the coiling of such stock, of a driving motor for said reel, an electromagnetic clutch for controlling adriving connection between said reel and said motor, means for establishing an energizing cirfor the coiling of such stock, of a driving motor for said reel, an electromagnetic clutch responsive to establish a driving connection between said motor and said reel, means for establishing an energizing circuit for said clutch but only upon starting of said motor, and means associated with said former means for varying the value of the current supplied to said clutch to provide for slippage thereof at given limited torques upon commencement of a winding operation and upon stopping of said machine during a winding operation and to also render the same non-slipping after commencement of a winding operation.

5. The combination with a strip mill, of a reel for winding strip material delivered by said mill, a driving motor for said reel, an electromagnetic clutch responsive to establish a driving connection between said motor and said reel, means for establishing an energizing circuit for said clutch and for varying the current supplied thereto to provide for slippage thereof upon commencement of a winding operation and to render the same non-slipping after the strip between said reel and said motor becomes taut and means for controlling the current supplied to said motor to maintain a substantially constant tension on the strip during winding thereof.

6. The combination with a strip mill, of a reel for winding strip material delivered by said mill, a driving motor for said reel, an electromagnetic clutch responsive to establish a driving connection between said motor and said reel, means responsive only upon engagement of said clutch to control said motor to maintain a, substantially constant tension on the strip during winding thereof, means for establishing an energizing circuit for said clutch but only upon starting of said motor, and means associated with said latter means for controlling the current supplied to said clutch to rovide for slippage thereof upon commencement of a winding operation and for thereafter rendering the same non-slipping.

7. The combination with a strip mill, of a reel for winding strip material delivered by said mill, a driving motor for said reel, an electromagnetic clutch responsive to establish a driving connection between said motor and said reel, electroresponsive means operable only upon starting of said motor to establish an energizing circuit for said clutch, a resistance connected in the energizing circuit for said clutch, means normally excluding said resistance from said circuit and responsive upon a given current condition in said circuit to include the same, and manually controlled means for shunting a portion of said resistance.

8, The combination with a strip mill, of a collapsible reel for winding strip material delivered by said mill, said reel having a normally engaged electroresponsive brake associated therewith, a driving motor for sa'd reel, a clutch responsive to establish a driving connection between said motor and said reel, means for simultaneously energizing said brake and said clutch but only upon starting of said motor, and for simultaneously deenergizing said clutch and said brake upon complet on of a winding operation, said means including means for preventing deenergization of said clutch and said brake except upon positioning of said reel in a given angular position.

PAISLEY B. HARWOOD. NIELS L. MOR'IENSEN. 

